GM Service Manual Online
For 1990-2009 cars only

Special Tools

J 39946 Crankshaft Socket

Removal Procedure

  1. Remove the engine oil pump. Refer to Oil Pump Replacement.

  2. Object Number: 517185  Size: SH
  3. Align the primary timing marks (1) using the J 39946 .

  4. Object Number: 928392  Size: SH
  5. Remove the 2 bolts attaching the primary camshaft drive chain tensioner to the engine block.
  6. Remove the primary camshaft drive chain tensioner, allowing the tensioner to expand as you remove it.
  7. Clean and inspect the camshaft timing drive components. Refer to Camshaft Timing Drive Components Cleaning and Inspection.

Installation Procedure


    Object Number: 240843  Size: SH
  1. Collapse the primary camshaft drive chain tensioner using the following procedure:
  2. 1.1. Rotate the ratchet release lever (2) clockwise and hold.
    1.2. Collapse the tensioner shoe (1) and hold.
    1.3. Release the ratchet lever (2).
  3. Slowly release the pressure on the shoe (1), until the ratchet lever (2) moves to the first detent and a click is heard and felt.
  4. Collapse the tensioner shoe (1) and hold.

  5. Object Number: 52989  Size: SH
  6. Insert a pin through the hole in the release lever in order to lock the tensioner shoe in the collapsed position.
  7. Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 928392  Size: SH

    Note: Ensure the tensioner release lever is facing outward.

  8. Install the primary camshaft drive chain tensioner and retaining bolts and tighten to 25 N·m (18 lb ft).
  9. Remove the pin holding the tensioner to tighten any slack in the timing chain.

  10. Object Number: 517185  Size: SH
  11. Ensure the primary timing marks (1) are aligned vertically.
  12. Install the engine oil pump. Refer to Oil Pump Replacement.